This disclosure relates generally to data storage systems, and systems and methods to improve storage efficiency, compactness, performance, reliability, and compatibility. Magnetic disk storage devices, such as hard disk drives, provide large amounts of affordable storage. However, magnetic disk storage devices often include an internal write buffer for storing write data before it is written to disk. Write data stored in the internal write buffer is at risk of loss if there is a power failure. Magnetic disk storage devices may be configured so that write operations are only acknowledged after the write data has been stored on disk, as opposed to the internal write buffer; however, this reduces write performance greatly. More specialized hardware, such as hardware RAID controllers, may include battery or supercapacitor power backups to preserve data in the write buffer in the event of a power failure; however, these hardware components increase the cost and complexity of systems.
In contrast, many relatively low-cost solid-state disk drives (SSDs) include a backup power source, such as a battery or supercapacitor, to preserve write data in the write buffer in the event of a power failure. However, SSDs are much more expensive than magnetic disk drives of similar storage capacity. Thus, most low-cost SSDs have much smaller storage capacities than typical magnetic disk drives.